Property Attribute Reference

This page is a full reference for the property-level attributes available in Cognibase.

Attribute Hierarchy

SecurityObjectAttribute
└── PropertyAttribute
    ├── RuntimePropertyAttribute       [RuntimeProperty]
    │   └── PersistedPropertyAttribute [PersistedProperty]
    ├── CalculativePropertyAttribute   [CalculativeProperty]
    └── IndirectPropertyAttribute      [IndirectProperty]

[PersistedProperty]

Applied to properties that are saved to the database and synchronized across all nodes.

[PersistedProperty]
public string Description { get => getter<string>(); set => setter(value); }

[PersistedProperty] extends [RuntimeProperty] and inherits all options listed in the [RuntimeProperty] section below.

Persistence-Specific Options

Option	Type	Default	Description
AutoValue	AutoValue	None	AutoValue.Identity makes the column an auto-increment primary key
PersistedAs	string	(property name)	Overrides the database column name

Identity Key Pattern

Use IdOrder (inherited from [RuntimeProperty]) together with AutoValue.Identity to declare primary keys:

// Single auto-increment identity key
[PersistedProperty(IdOrder = 1, AutoValue = AutoValue.Identity)]
public long Id { get => getter<long>(); set => setter(value); }

// Composite key — two fields together form the unique identifier
[PersistedProperty(IdOrder = 1)]
public long RegionId { get => getter<long>(); set => setter(value); }

[PersistedProperty(IdOrder = 2)]
public long SequenceNo { get => getter<long>(); set => setter(value); }

// String-based natural key
[PersistedProperty(IdOrder = 1)]
public string IsoCode { get => getter<string>(); set => setter(value); }

[RuntimeProperty]

Applied to properties that are distributed in real-time but are never saved to the database. Can appear on both [RuntimeClass] and [PersistedClass] entities:

[RuntimeProperty]
public bool IsAlive { get => getter<bool>(); set => setter(value); }

Data-Source Options

Option	Type	Default	Description
DataSourceType	DataSourceType	Internal	How the framework locates the backing storage for this property
DataSourceName	string	null	Name of the backing field or data source
IdOrder	int	-1	Position of this property in the composite primary key; -1 means not part of the key
DefaultValue	object	null	Value assigned to new instances when no explicit value is provided

Validation Options

Option	Type	Default	Description
IsMandatory	bool	false	Rejects null (and empty string) values
Min	double	—	Minimum numeric value (applies to numeric types)
Max	double	—	Maximum numeric value (applies to numeric types)
MinDate	string	""	Minimum allowed date (ISO 8601 string)
MaxDate	string	""	Maximum allowed date (ISO 8601 string)
MinTimeSpan	string	""	Minimum allowed TimeSpan (string format)
MaxTimeSpan	string	""	Maximum allowed TimeSpan (string format)
IsWriteOnce	bool	false	Value can be set at creation but cannot be changed afterwards
ValueList	string	""	Pipe-separated list of valid values

Relationship Options

Option	Type	Default	Description
AssociationType	AssociationType	Association	Association, CompositionParent, or CompositionChild
ReverseRef	string	null	Name of the corresponding property on the related class (enables bidirectional navigation)
IsProxyRef	bool	false	Marks this property as a proxy reference

Change-Stream and Loading Options

Option	Type	Default	Description
ChangeStreamMode	ChangeStreamMode	Delegate	Streaming behaviour for change events on this property
FieldLoadErrorMonitorMode	FieldLoadErrorMonitorMode	On	Whether load errors on this field are monitored
FieldLoadErrorReportMode	FieldLoadErrorReportMode	Delegate	How load errors on this field are reported
FieldLoadErrorValueDeliveryMode	FieldLoadErrorValueDeliveryMode	Delegate	What value is returned when a load error occurs
FieldLoadErrorValue	object	null	The specific fallback value delivered on load error
FieldLoadAgingMode	FieldLoadAgingMode	Delegate	Whether this field's value ages out over time
FieldLoadAgingDelay	string	""	Duration before the field value is considered stale
IsNotifyForImplicitFieldSaveEvent	bool	false	Raises a save event when the field is implicitly modified
IsMethodData	bool	false	Indicates the property value comes from a method call

Example — Full Property Annotation

[PersistedClass]
public class Tile : DataItem
{
    // Auto-increment identity key
    [PersistedProperty(IdOrder = 1, AutoValue = AutoValue.Identity)]
    public long Id { get => getter<long>(); set => setter(value); }

    // Mandatory string with a custom column name in the database
    [PersistedProperty(IsMandatory = true, PersistedAs = "tile_description")]
    public string Description { get => getter<string>(); set => setter(value); }

    // Numeric fields with range constraints
    [PersistedProperty(DefaultValue = 0.0f)]
    public float X { get => getter<float>(); set => setter(value); }

    [PersistedProperty(DefaultValue = 0.0f)]
    public float Y { get => getter<float>(); set => setter(value); }

    [PersistedProperty(Min = 0.1, Max = 10.0, DefaultValue = 1.0f)]
    public float Scale { get => getter<float>(); set => setter(value); }

    // Write-once serial number
    [PersistedProperty(IsWriteOnce = true)]
    public string SerialNumber { get => getter<string>(); set => setter(value); }

    // Runtime property — live state, not persisted
    [RuntimeProperty]
    public bool IsSelected { get => getter<bool>(); set => setter(value); }
}

[CalculativeProperty]

A calculative property returns a value computed entirely by your code. It is neither persisted nor distributed to other nodes.

[CalculativeProperty]
public string DisplayLabel => $"[{Code}] {Name}";

Options

Option	Type	Description
DataSourceName	string	Name of the underlying data source used during calculation
Getter	string	Name of a method that provides the value (alternative to a lambda expression)
BindingFlags	BindingFlags	Reflection flags used to locate the Getter method

Example — Using a Named Getter Method

[CalculativeProperty(Getter = nameof(ComputeStatus))]
public string Status { get; }

private string ComputeStatus()
{
    return IsOnline ? $"Online ({LastSeen:HH:mm})" : "Offline";
}

[IndirectProperty]

An indirect property navigates through a reference chain to expose a value from a related object. It is neither persisted nor distributed.

// Exposes the name of the category this product belongs to
[IndirectProperty(Target = "Category.Name")]
public string CategoryName { get; }

Options

Option	Type	Description
Target	string	Dot-separated navigation path to the source value

Example — Multi-Level Navigation

[PersistedClass]
public class Tile : DataItem
{
    [PersistedProperty(AssociationType = AssociationType.CompositionChild,
        ReverseRef = nameof(Canvas.Tiles))]
    public Canvas Canvas { get => getter<Canvas>(); set => setter(value); }

    // Navigates Canvas → Name
    [IndirectProperty(Target = "Canvas.Name")]
    public string CanvasName { get; }
}

Shared Options (from PropertyAttribute)

All property attributes inherit the following display and UI options:

Option	Type	Default	Description
Description	string	""	Human-readable description
ResourceId	string	null	Resource key for localization
DisplayFormat	string	null	Format string for display
EditMask	string	null	Input mask for editing
IsDisplayed	bool	true	Whether this property is shown in auto-generated UI
SignatureOrder	int	-1	Position of this property in the object's signature string
SignaturePrefix	string	null	Prefix added before this property's contribution to the signature
SignatureSuffix	string	null	Suffix added after this property's contribution to the signature
TabIndex	int	0	Tab order in auto-generated forms
GroupName	string	""	Groups related properties together in auto-generated UI
HierarchyParent	bool	false	Marks this property as the parent link in a tree hierarchy
HierarchyChildren	bool	false	Marks this property as the children collection in a tree hierarchy
EditorType	Type	null	Custom editor component type
EditorTypeId	DefaultTypeEditorId	None	Built-in editor identifier
EditorContext	string	null	Context string passed to the editor
ViewAsType	Type	null	Custom view component type
EmptySpecifier	object	null	The value considered "empty" for this property
IsNotifiedOnReferenceChange	bool	false	Raise a change notification when the referenced object itself changes
MemberType	Type	null	Override the reported member type
ValueFormatterType	Type	null	Custom formatter for display values

Security Options (inherited from SecurityObjectAttribute)

Option	Type	Default	Description
SecurityEnabled	bool	true	Whether security checks apply to this property
SecurityLabel	string	""	Label shown in security management UI
SecurityHeader	string	""	Column header in security lists
SecurityDescription	string	""	Description in security management UI
SecurityDisplayOrder	int	0	Sort order in security management lists

Supported Scalar Types

Cognibase maps the following C# types to native database columns:

C# Type	Notes
string	Variable-length text
bool	Boolean flag
int	32-bit integer
long	64-bit integer (common for identity keys)
float	Single-precision floating-point
double	Double-precision floating-point
decimal	High-precision decimal
DateTime	Date and time
TimeSpan	Duration
Guid	Globally unique identifier
Any C# enum	Stored as its underlying integer value
BLOB	Binary large object (raw bytes)
ImageBLOB	Image binary data with metadata

Synchronization Constraints with [SyncReq]

When two properties on the same class must always be saved together — for example a pair of coordinates — annotate the class with [SyncReq] to instruct the framework to include both in every save event:

[SyncReq(nameof(Longitude), nameof(Latitude))]
[PersistedClass]
public class GeoPoint : DataItem
{
    [PersistedProperty(IdOrder = 1, AutoValue = AutoValue.Identity)]
    public long Id { get => getter<long>(); set => setter(value); }

    [PersistedProperty]
    public double Longitude { get => getter<double>(); set => setter(value); }

    [PersistedProperty]
    public double Latitude { get => getter<double>(); set => setter(value); }
}

Multiple [SyncReq] attributes can be placed on the same class.

Gate Mapping Options

Property attributes support a set of Gate options that bind Cognibase properties to external data sources (gateways). These are used when integrating Cognibase with legacy systems or real-time data feeds:

Option	Type	Description
GateName	string	Name of the gateway to use
GateType	string	Type identifier of the gateway
GateId	string	Identifier within the gateway
GateMapMode	GateMapMode	How the mapping is applied
GateDataSourceId	string	Data-source identifier within the gateway
GateWriteActionName	string	Name of the write action on the gateway
GateLoadHint	string	Hint passed to the gateway on load
IsGateDataSourcePath	bool	Treats GateDataSourceId as a path
IsGateLoadHint	bool	Enables the load hint
IsGateWritable	bool	Enables write-back to the gateway